COCI '21 Contest 5 #4 Radio

View as PDF

Submit solution


Points: 17 (partial)
Time limit: 1.5s
Memory limit: 512M

Problem type

In Croatia there are n radio stations. Each station has a concession on one of n frequencies denoted by positive integers from 1 to n. The frequencies were not chosen ideally so sometimes noise appears when multiple stations are broadcasting at the same time. To be more precise, if two radio stations, with frequencies a and b respectively, are broadcasting at the same time, noise will appear if a and b are not relatively prime. The listeners, of course, do not like the noise, so when they hear it they switch to another station.

To solve this noise problem, the radio station owners are asking you to write a program which simulates the actions of the radio stations. Your program needs to support two types of queries:

  1. S x: If not currently broadcasting, the station with frequency x starts broadcasting, and if it is already broadcasting, it stops.

  2. C l r: Check if there exists a pair of broadcasting stations whose frequencies a and b are from the interval [l,r] and such that gcd(a,b)1. If such a pair exists, print DA, otherwise print NE.

Initially, no station is broadcasting.

Input Specification

The first line contains positive integers n and q, the number of radio stations (and frequencies), and the number of queries, respectively.

The ith of the next q lines contains a description of the ith query. For queries of the first type it will hold that 1xn, and for queries of the second type it will hold that 1lrn.

Output Specification

Print the answers to the queries of the second type in order, in separate lines.

Constraints

SubtaskPointsConstraints
1101n100, 1q200
230For all queries of the second type it holds that l=1 and r=n.
3701n106, 1q2×105

Sample Input 1

Copy
6 8
S 1
S 2
S 3
C 1 6
S 6
C 1 6
S 2
C 1 6

Sample Output 1

Copy
NE
DA
DA

Explanation for Sample Output 1

The stations broadcasting during the first C type query are 1, 2 and 3. These numbers are all relatively prime to each other so they create no noise. Once station 6 begins to broadcast, it creates noise with stations 2 and 3. After station 2 stops broadcasting the noise with station 3 persists.

Sample Input 2

Copy
11 6
S 4
S 10
C 3 11
C 2 7
S 6
C 2 7

Sample Output 2

Copy
DA
NE
DA

Sample Input 3

Copy
20 7
S 10
S 15
S 3
C 10 15
S 10
C 3 15
C 3 10

Sample Output 3

Copy
DA
DA
NE

Comments

There are no comments at the moment.